The large amount of non-biodegradable sulfonamide antibiotics used in hospitals, feedstocks and in fish farming cause their occurrence in the aquatic environment resulting in the dramatic emergence of antibiotic resistance in fish pathogens and in the transfer of these resistance determinants to bacteria in land animals and to human pathogens [1]. In Italy, it was found that sulfamethoxazole (SMX) is one of the most abundant residual drug in surface waters [2]. Recently, it has been proven that high-silica zeolites (Y, ZSM-5 and MOR) are environmentally compatible adsorbents able to effectively remove sulfamethoxazole when dissolved in aqueous matrix [3]. The effective incorporation of this pollutant inside the zeolite cavities has been demonstrated by combining diffraction and spectroscopic techniques [3]. In this work, the thermal regeneration of hydrophobic high-silica ZSM-5 and hydrophobic high-silica zeolite Y after sulfamethoxazole adsorption was investigated using in situ high-temperature synchrotron X-ray powder diffraction (GILDA, ESRF) to monitor the structural modifications induced by heating. The evolution of the structural features was followed both in temperature ramp (25-575°C, heating rate 10 °C/min) and in isotherm mode (120 minutes at 575 °C) by full profile Rietveld refinements. Structure refinements demonstrate that the thermal regeneration accompanied by the full degradation of SMX is completed at about 575 °C and it does not affect the crystallinity of the sorbing materials. These results indicate that high-silica zeolite Y and high silica ZSM-5 are affordable materials for water clean-up and drug delivery.
Regeneration of organophilic zeolites after sulfomethoxazole antibiotic adsorption
MARTUCCI, Annalisa;
2013
Abstract
The large amount of non-biodegradable sulfonamide antibiotics used in hospitals, feedstocks and in fish farming cause their occurrence in the aquatic environment resulting in the dramatic emergence of antibiotic resistance in fish pathogens and in the transfer of these resistance determinants to bacteria in land animals and to human pathogens [1]. In Italy, it was found that sulfamethoxazole (SMX) is one of the most abundant residual drug in surface waters [2]. Recently, it has been proven that high-silica zeolites (Y, ZSM-5 and MOR) are environmentally compatible adsorbents able to effectively remove sulfamethoxazole when dissolved in aqueous matrix [3]. The effective incorporation of this pollutant inside the zeolite cavities has been demonstrated by combining diffraction and spectroscopic techniques [3]. In this work, the thermal regeneration of hydrophobic high-silica ZSM-5 and hydrophobic high-silica zeolite Y after sulfamethoxazole adsorption was investigated using in situ high-temperature synchrotron X-ray powder diffraction (GILDA, ESRF) to monitor the structural modifications induced by heating. The evolution of the structural features was followed both in temperature ramp (25-575°C, heating rate 10 °C/min) and in isotherm mode (120 minutes at 575 °C) by full profile Rietveld refinements. Structure refinements demonstrate that the thermal regeneration accompanied by the full degradation of SMX is completed at about 575 °C and it does not affect the crystallinity of the sorbing materials. These results indicate that high-silica zeolite Y and high silica ZSM-5 are affordable materials for water clean-up and drug delivery.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
